CN117305550A - Method for inducing growth of austenitic stainless steel dendrites - Google Patents
Method for inducing growth of austenitic stainless steel dendrites Download PDFInfo
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- CN117305550A CN117305550A CN202311125318.8A CN202311125318A CN117305550A CN 117305550 A CN117305550 A CN 117305550A CN 202311125318 A CN202311125318 A CN 202311125318A CN 117305550 A CN117305550 A CN 117305550A
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- 238000000034 method Methods 0.000 title claims abstract description 32
- 210000001787 dendrite Anatomy 0.000 title claims abstract description 17
- 229910000963 austenitic stainless steel Inorganic materials 0.000 title claims abstract description 12
- 230000001939 inductive effect Effects 0.000 title claims abstract description 11
- 238000010894 electron beam technology Methods 0.000 claims abstract description 45
- 238000012360 testing method Methods 0.000 claims abstract description 27
- 239000010963 304 stainless steel Substances 0.000 claims abstract description 19
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 claims abstract description 19
- 238000005498 polishing Methods 0.000 claims abstract description 15
- 238000012545 processing Methods 0.000 claims abstract description 13
- 238000005520 cutting process Methods 0.000 claims abstract description 8
- 238000004140 cleaning Methods 0.000 claims abstract description 7
- 238000002360 preparation method Methods 0.000 claims abstract description 7
- 238000003801 milling Methods 0.000 claims abstract description 4
- 238000007781 pre-processing Methods 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 14
- 230000008569 process Effects 0.000 claims description 12
- 244000137852 Petrea volubilis Species 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 6
- 238000003466 welding Methods 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 238000004381 surface treatment Methods 0.000 claims 1
- 238000005260 corrosion Methods 0.000 abstract description 4
- 230000007797 corrosion Effects 0.000 abstract description 4
- 238000012986 modification Methods 0.000 description 15
- 230000004048 modification Effects 0.000 description 15
- 239000011159 matrix material Substances 0.000 description 5
- 239000010410 layer Substances 0.000 description 4
- 238000005299 abrasion Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention discloses a method for inducing growth of austenitic stainless steel dendrites, which specifically comprises the following steps: step 1: and (3) preprocessing, namely cutting and milling the test block workpiece, processing the test block workpiece into a fixed size and a fixed shape, and cleaning the processed workpiece by using an ultrasonic cleaner. Step 2: sample preparation, and polishing the test block by using a metallographic polishing machine. Step 3: and E, electron beam treatment, wherein the electron beam is adopted to carry out multiple irradiation treatment on the sample. Step 4: and (3) tissue and performance testing, wherein a scanning electron microscope is adopted to observe a microstructure, and a frictional wear testing machine is utilized to detect the wear resistance of the microstructure. Namely, the method disclosed by the invention can obviously improve the wear resistance and corrosion resistance of the surface of the 304 stainless steel, and has excellent application scenes.
Description
[ field of technology ]
The invention belongs to the technical field of stainless steel high-energy beam surface modification, and particularly relates to a method for treating 304 stainless steel by high-voltage and low-frequency electron beams.
[ background Art ]
With the development of manufacturing industry, the current demand for steel still keeps in an ascending stage, and how to make the mechanical structure and parts meet the severe working conditions, and prolong the service life of the mechanical structure and parts is an important subject for improving national economy. The 304 stainless steel is a common austenitic stainless steel, has good machining performance, and is widely used in medical appliances, industrial furniture decoration industry, food medical industry and the like. However, with the development of the social industry, the parts such as the plate heat exchanger, the corrugated pipe and the like need high-precision, high-wear-resistance and high-corrosion-resistance process requirements, the common heat treatment mode cannot meet the increasingly developed industrial requirements, and the service life is increasingly shortened. To solve this problem, the work piece is generally subjected to surface strengthening treatment to improve the fatigue, wear and corrosion resistance of the surface, and to extend the work piece life. The traditional metal surface strengthening treatment comprises surface quenching, electroplating, carburizing, nitriding, heat treatment and the like, but the strengthening method is limited in practical application due to various reasons such as time and labor consumption, high cost, serious pollution and the like. Therefore, it is a necessary trend to explore more efficient, lower cost, and more environmentally friendly treatment processes.
The electron beam surface modification treatment is a process method that the electron beam acts on the surface of the material to enable the shallow surface layer of the material to be subjected to strong melting, and the shallow surface layer instantaneously transmits heat to the substrate because the substrate is still in a cold state, and the composition and the tissue structure change after rapid cooling, so that the required performance is achieved. Compared with other material surface modification techniques, the electron beam surface modification treatment has the following advantages:
(1) The power density is high, the control is flexible, the repeatability is good, and the surface temperature and the penetration depth can be accurately controlled;
(2) The method is carried out under the vacuum condition, so that the metal is well protected, and higher binding force and performance can be obtained, thereby ensuring the quality.
Therefore, the patent proposes to adopt a scanning electron beam surface modification method to carry out surface modification on the 304 stainless steel, the electron beam surface modification is to bombard the surface of the material by electron beams, so that the temperature of the surface of the material is rapidly increased, and then the material is rapidly cooled, thereby achieving the effect of dendrite growth, because dendrite growth along an ideal direction can promote the wear resistance and corrosion resistance of the 304 stainless steel, and the mechanism research and experimental conclusion is applied to the surface modification of other metal materials, and the surface processing field of the high-energy beam material is expanded.
[ invention ]
The purpose of the invention is that:
according to the invention, 304 stainless steel is processed into a fixed size and shape, and a metallographic polishing machine is adopted for polishing to obtain a sample; and then the sample finished product is obtained through scanning electron beam surface modification treatment. The invention effectively improves the abrasion resistance and corrosion resistance of the surface of the test block and has excellent practical application scene.
In order to solve the problem, the invention adopts the following technical scheme: a method of inducing dendrite growth in austenitic stainless steel comprising the steps of:
1. a method of inducing dendrite growth in austenitic stainless steel comprising the steps of:
step 1: and (3) preprocessing, namely cutting and milling the test block workpiece, processing the test block workpiece into a fixed size and a fixed shape, and cleaning the processed workpiece by using an ultrasonic cleaner to remove oil stains and impurities on the surface.
Step 2 is carried out after the step 1 is finished;
step 2: sample preparation, namely sequentially polishing from 600-mesh sand paper to 3000-mesh sand paper by using a metallographic polishing machine and polishing.
Step 3 is carried out after the step 2 is finished;
step 3: electron beam processing, placing the sample in a thermal processing chamber of an electron beam welding machine, and vacuumizing to make the vacuum degree of the electron gun chamber 1.33X10 -3 Pa, process chamber vacuum of 5X 10 -2 Pa. Setting the technological parameters of an electron beam welding process, wherein the accelerating voltage of an electron beam is 120kV, the focusing current is 800mA, the beam current of the electron beam is 15mA, the frequency of the electron beam is 50Hz, the time of the electron beam is 20ms, and the radius of the beam spot of the electron beam is 3mm. And then cutting the treated sample into small blocks, cleaning the test blocks by using an ultrasonic cleaner, and performing metallographic sample preparation to obtain a finished product.
Step 3, after finishing the step 4;
step 4: and (3) tissue and performance testing, namely observing the microstructure of the sample by using a Quanta FEG450 field emission Scanning Electron Microscope (SEM), and performing a friction and wear test on the sandpaper polished surface of the sample by using a CFT-I type material surface performance comprehensive tester, wherein a 30N loading load, a 3mm reciprocating length, a rotating speed of 300r/min and a 15min duration are selected.
2. A method of inducing dendrite growth in austenitic stainless steel according to claim 1, characterized in that: and (3) cutting the 304 stainless steel workpiece into test blocks of 10mm multiplied by 15mm multiplied by 5mm before the step (1), and performing metallographic polishing.
3. A method of inducing dendrite growth in austenitic stainless steel according to claim 1, characterized in that: and 3, carrying out surface modification by using high-voltage low-frequency electron beams.
4. A method of inducing dendrite growth in austenitic stainless steel according to claim 1, characterized in that: in the step 3, the electron beam with high voltage and low frequency is adopted to carry out surface modification on the sample, so that the effect of grain refinement and ideal dendrite growth can be obtained.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention adopts high-voltage and low-frequency electron beams to carry out surface modification on the surface of the 304 stainless steel, and can effectively improve the abrasion resistance of the surface of the sample. The invention adopts a high-voltage and low-frequency electron beam treatment mode, has high energy density, ensures that the 304 stainless steel is quickly heated to reach the melting point of the material, and then is quickly cooled. The rapid heating and quenching processes enable the sample modification layer and the matrix structure to be transformed, grains to be refined, dendrites to grow along the ideal direction, the anisotropy of mechanical properties is provided, and the abrasion resistance of the surface of the sample is greatly improved.
2. The process of treating 304 stainless steel by scanning electron beams is carried out in a vacuum processing chamber, so that the environment in the processing process is ensured to be pollution-free, and the 304 stainless steel is prevented from contacting the outside; meanwhile, the energy transfer medium is electrons, and has the characteristics of high energy conversion, good action effect and the like.
3. The friction coefficient of the 304 stainless steel matrix prepared by the invention is 1.0, and the friction coefficient of the modified layer is 0.6. The friction coefficient of the surface of the 304 stainless steel test block is obviously reduced after the electron beam treatment. The reciprocating length was 3mm under a load of 30N, and the friction coefficient was reduced from 1.0 to 0.6 of the matrix by 40% for 15 min.
[ description of the drawings ]
FIG. 1 is a schematic diagram of the electron beam operation of the present invention;
FIG. 2 is a cross-sectional structure of a 304 stainless steel obtained after the practice of the present invention;
FIG. 3 is an enlarged view of the microstructure of 304 stainless steel prior to the practice of the present invention;
FIG. 4 is a graph showing the friction coefficient test of 304 stainless steel obtained after the practice of the present invention;
[ detailed description ] of the invention
The following are specific embodiments of the present invention, and the embodiments of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.
A method of electron beam treating 304 stainless steel, comprising the steps of:
1. a method of electron beam treating 304 stainless steel, comprising the steps of:
step 1: and (3) preprocessing, namely cutting and milling the test block workpiece, processing the test block workpiece into a fixed size and a fixed shape, and cleaning the processed workpiece by using an ultrasonic cleaner to remove oil stains and impurities on the surface.
Step 2 is carried out after the step 1 is finished;
step 2: sample preparation, namely sequentially polishing from 600-mesh sand paper to 3000-mesh sand paper by using a metallographic polishing machine and polishing.
Step 3 is carried out after the step 2 is finished;
step 3: electron beam processing, placing the sample in a thermal processing chamber of an electron beam welding machine, and vacuumizing to make the vacuum degree of the electron gun chamber 1.33X10 -3 Pa, process chamber vacuum of 5X 10 -2 Pa. Setting the technological parameters of an electron beam welding process, wherein the accelerating voltage of an electron beam is 120kV, the focusing current is 800mA, the beam current of the electron beam is 15mA, the frequency of the electron beam is 50Hz, the time of the electron beam is 20ms, and the radius of the beam spot of the electron beam is 3mm. And then cutting the treated sample into small blocks, cleaning the test blocks by using an ultrasonic cleaner, and performing metallographic sample preparation to obtain a finished product.
Step 3, after finishing the step 4;
step 4: tissue and performance tests, namely observing the microstructure of a sample by using a Quanta FEG450 field emission Scanning Electron Microscope (SEM), and measuring the section microhardness of the sample by using an HDX-1000TM microhardness meter under the conditions of 100g load, 0.981N test force and 5s load time; and (3) carrying out a friction and wear test on the surface of the sample polished by the sand paper by adopting a CFT-I type material surface performance comprehensive tester, wherein a 30N loading load, a 3mm reciprocating length, a rotating speed of 300r/min and a 15min duration are selected.
And (3) carrying out a friction and wear test on the surface of the sample polished by the sand paper by adopting a CFT-I type material surface performance comprehensive tester, wherein a 30N loading load, a 3mm reciprocating length, a rotating speed of 300r/min and a 15min duration are selected. After treatment, the surface friction coefficient is reduced by 40 percent
Sample microstructures were tested using a Quanta FEG450 field emission Scanning Electron Microscope (SEM). As shown in FIG. 2, the cross section is divided into a modified layer and a matrix, the fusion lines of all areas are obvious, and the grains of the modified layer are obviously thinned, so that the matrix has good modification effect. Fig. 3 shows the effect of local modification, and it can be found that the grain refinement and dendrite growth are achieved, and the wear resistance of the material is greatly improved. And a fourth graph is a friction coefficient test graph, and the friction coefficient is obviously reduced.
The foregoing description is directed to specific details of possible examples of the present invention, but the embodiments are not limited to the scope of the present invention, and all equivalent changes or modifications made under the technical spirit of the present invention should be construed to fall within the scope of the present invention.
Claims (4)
1. A method of inducing dendrite growth in austenitic stainless steel comprising the steps of:
step 1: and (3) preprocessing, namely cutting and milling the test block workpiece, processing the test block workpiece into a fixed size and a fixed shape, and cleaning the processed workpiece by using an ultrasonic cleaner to remove oil stains and impurities on the surface.
Step 2 is carried out after the step 1 is finished;
step 2: sample preparation, namely sequentially polishing from 600-mesh sand paper to 3000-mesh sand paper by using a metallographic polishing machine and polishing.
Step 3 is carried out after the step 2 is finished;
step 3: electron beam processing, placing the sample in a thermal processing chamber of an electron beam welding machine, and vacuumizing to make the vacuum degree of the electron gun chamber 1.33X10 -3 Pa, process chamber vacuumDegree of 5×10 -2 Pa. Setting the technological parameters of an electron beam welding process, wherein the accelerating voltage of an electron beam is 120kV, the focusing current is 800mA, the beam current of the electron beam is 15mA, the frequency of the electron beam is 50Hz, the time of the electron beam is 20ms, and the radius of the beam spot of the electron beam is 3mm. And then cutting the treated sample into small blocks, cleaning the test blocks by using an ultrasonic cleaner, and performing metallographic sample preparation to obtain a finished product.
Step 3, after finishing the step 4;
step 4: tissue and performance testing, observing the microstructure of the sample by using a Quanta FEG450 field emission Scanning Electron Microscope (SEM); and (3) carrying out a friction and wear test on the surface of the sample polished by the sand paper by adopting a CFT-I type material surface performance comprehensive tester, wherein a 30N loading load, a 3mm reciprocating length, a rotating speed of 300r/min and a 15min duration are selected.
2. A method of inducing dendrite growth in austenitic stainless steel according to claim 1, characterized in that: the pretreatment in the step 1 is to cut and mill the 304 stainless steel workpiece into test blocks of 10mm multiplied by 10mm, and carry out metallographic polishing.
3. A method of inducing dendrite growth in austenitic stainless steel according to claim 1, characterized in that: and 3, carrying out surface treatment by adopting high-voltage and low-frequency electron beams.
4. A method of electron beam treatment 304 of stainless steel according to claim 1, characterized in that: and 3, the material after the treatment in the step can obtain the effects of grain refinement and dendrite growth.
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| CN202311125318.8A CN117305550A (en) | 2023-09-01 | 2023-09-01 | Method for inducing growth of austenitic stainless steel dendrites |
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| CN202311125318.8A CN117305550A (en) | 2023-09-01 | 2023-09-01 | Method for inducing growth of austenitic stainless steel dendrites |
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- 2023-09-01 CN CN202311125318.8A patent/CN117305550A/en active Pending
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